1. Field of the Invention
The present invention relates in general to the field of interfacing circuit boards, and more particularly to a method and system for coupling information handling system circuit boards in a parallel configuration.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
One common goal of information handling system manufacturers is to efficiently configure electronic components to include as much functionality as possible in as little room as practical. To aid in the efficient use of space, low profile board-to-board connectors are sometimes used for a high density component configuration solution in which circuit boards are connected together with their surfaces aligned parallel to each other. For instance, a daughterboard couples to connectors disposed on a motherboard surface so that the daughterboard and motherboard surfaces are in parallel alignment with a standoff height board-to-board distance of 4 mm or less. One difficulty with such configurations is that the small amount of space between the circuit cards leaves little room for attachment or support mechanisms to retain the circuit boards in position relative to each other. Another difficulty is that the relatively small clearances between the circuit boards makes visual alignment of connectors difficult with little pin lead-in between connectors, sometimes resulting in bent pins where the circuit boards are not accurately guided into each other. Although one option is to enlarge the room between the circuit boards, increasing this spacing increases the vertical footprint of the information handling system.
A number of connectors exist to connect circuit boards in a parallel alignment. Frictional connectors align the cards and manually mate with each other so that the mating force of the connectors couples the boards together. However, these connectors are often not sufficiently secure and allow excessive fluctuations in standoff height, possibly resulting in poor electrical communications between the boards. Snap standoff posts snap into both boards with a post typically equal in length to the board-to-board dimension and generally are used only for permanent board connections. Similarly, board edge levers apply force on a portion of the board, typically along the edge, with a lever or secondary part that allows removal of the board but is awkward to manipulate. Another option is to dispose standoff pieces between the circuit boards and then couple the boards together with screws so that the standoff pieces maintain spacing between the circuit boards. However, these standoff pieces increase the complexity of manufacturing the circuit boards and are difficult to use in a manner that maintains both a desired standoff height and a sound electrical connection between the circuit boards.
Therefore a need has arisen for a method and system which quickly and securely couples circuit boards in a parallel configuration with a low profile.
A further need exists for a method and system which maintains a sound electrical connection between the connectors of circuit boards having a parallel configuration.
A further need exists for a method and system that aligns connectors of the circuit boards having a parallel configuration when the physical view of the connectors is blocked during mating of the connectors.
A further need exists for a method and system which couples circuit boards in a parallel configuration by mating multiple separate electrical connectors between the circuit boards.
In accordance with the present invention, a method and system are provided which substantially reduce the disadvantages and problems associated with previous methods and systems for coupling circuit boards together in a parallel configuration. A retention post and retaining member assembly aligns and mates connectors of the circuit boards and transfers mating force over the connectors to couple connectors together and retain the circuit boards in a parallel configuration.
More specifically, a retention post extends perpendicular from the surface of a motherboard. Connector sockets are disposed in the motherboard surface proximate to the retention post. A daughterboard aligns with the motherboard by aligning an opening of the daughterboard with the retention post and inserting the retention post through the opening. Connectors are disposed in the daughterboard surface proximate the opening so that insertion of the retention post into the opening guides the connectors into the connector sockets. A bow spring retaining member has flexible arms that extend from a raised central portion so that the retention post inserts into an opening of the bow spring central portion to align the arms with the connectors. A fastener, such as a captive screw or thumbscrew, tightens to selectable positions of the retention post to mate the connectors and to exert a retaining force that maintains the daughterboard in a parallel configuration relative to the motherboard. The flexible arms act as a spring to take up excess tightening torque applied to the connectors by the tightening of the thumbscrew fastener. The bow spring retaining member raises the thumbscrew fastener to a height just below the vertical footprint of an information handling system so that it is easily accessed without increasing the profile of the parallel configuration of the circuit boards.
The present invention provides a number of important technical advantages. One example of an important technical advantage is that circuit boards are quickly and securely coupled together in a parallel configuration with a low profile. The raised portion of the bow spring provides a solid area to apply mating force when initially engaging a daughterboard to reduce the risk that an assembler will push on the circuit boards or components during installation. The bow spring provides reliable mating of connectors by creating a direct preload on each connector. Further, the thumbscrew fastener is elevated from the daughterboard surface to provide ease of access for tightening and removal of the daughterboard.
Another example of an important technical advantage of the present invention is that a sound electrical connection is maintained between the connectors of circuit boards having a parallel configuration. Using multiple connectors allows the flexible bow spring to distribute the retention force substantially evenly directly to each connector to ensure a solid electrical connection even should the circuit cards have some vertical standoff fluctuations. The retention force is thus evenly applied for all connector pins regardless of the distance between the retention post and a given connector pin. The bow spring also flexes to avoid the application of excessive retention force that could damage the daughterboard.
Another example of an important technical advantage of the present invention is that connectors of circuit boards having a parallel configuration are effectively aligned although the parallel configuration blocks the physical view during mating of the connectors. The retention post aligns the daughterboard by inserting in an appropriately placed opening of the daughterboard. This alignment aids in proper mating of connectors that are hidden from view as the daughterboard is placed over the motherboard for assembly. Proper alignment reduces the risk of bent pins in low profile applications.